Insulated tank for liquefied hydrocarbons and the like with loose membranous lining therefor



ug- 1, 1961 W. MORRISON INSULATED TANK FOR LIQUEFIED HYDROCARBONS ANDTHE LIKE WITH LoosE MEMBRANOUS LINING THEREFOR Filed Aug. 2. 1954INVENTOR, Willard L. Morrison By Parker Bx Carter ATTORNEY 2,994,452INSULATED TANK FOR LIQUEFIED HYDROCAR- BONS AND THE 'LHE WITH LOOSE MEM-BRANOUS LHING THERE'FR Willard L. Morrison, Lake Forest, Ill., assigner,by mesne assignments, to Couch International Methane Limited, Nassau,Bahamas, a `corporation of the Bahamas Filed Aug. 2, 1954, Ser. No.447,037 2 Claims. (Cl. 220-9) My invention relates to improvements intanks for holding liquids and especially such liquids as liquefiedhydrocarbons, the liquid temperature or boiling point of which atatmospheric pressure is exceedingly low.

One object of the invention is to provide a tank which will hold with aminimum of evaporation such a liquelied hydrocarbon as methane which atatmospheric pressure boils at \-258 F.

I propose a metal tank of such strength as to support the hydrostaticpressure of the liquid contained therein, the tank being designed tosupport only the hydrostatic pressure and being not designed to supportgas pressure above atmospheric more than just enough to permit the vaporas the liquid changes from liquid to gaseous stage to discharge from thetank.

I propose to line the metal tank with an insulating mass which willprotect the metal tank from the cold of the liquid hydrocarbon so thatlittle if any condensation of moisture from the air on the outside ofthe tank will occur and so that the tank from a metallurgical point ofview may be designed from the point of view of normal atmospherictemperatures rather than the low temperature characteristic of themethane in liquid phase.

I propose to place inside of the insulating lining a liquid and gasimpervious lining or bag which will be loosely contained within theinsulating lining and will effectively prevent penetration of liquidinto the .insulating lining. Preferably also it will prevent penetrationof gas into the insulating lining though this is not as important aspenetration of the liquid into and through the lining so that the metalshell will at all times be protected against the cold of the liquid.

The impervious lining or bag will be so arranged that it approximatelylits the inside of the insulating lining. It will be loosely suspendedtherein so that expansion and contraction of the insulating lining andof the metal shell will have no eifect on the bag itself. The bag willbe suspended at the top around the outer periphery of the shell orintermediate the outer periphery and center of the shell, will hang downalong the inner boundary of the insulating lining and will rest on theinsulating floor of the shell or tank. When the tank is empty this bagwill hang free. When the tank is lled with liquid, the hydrostaticpressure of the liquid will hold the bag or impervious lining againstthe insulating lining.

As heat enters through the outer shell, the insulating lining and theimpervious lining, vaporization of the gas Will occur and developsuicient pressure in the order of an inch or so of water to cause thegas to escape from the tank through an open discharge aperture to apoint of use of other treatment. This may cause slight intlation of thebag at its top where it is not in contact actually with the liquid. Itis important that no substantial pressure be developed in the tankbecause as above indrcated, the tank shell is not designed to supportsuch a pressure.

I propose to make the impervious lining out of an inert material, forexample, glass ber cloth and to coat this cloth or impregnate this clothwith a plastic chemically inert to liquid or gaseous methane and havingsuch physical characteristics as will leave it suthcrently ilexrblegatita under the very low temperatures involved so that the Y imperviouslining may be displaced by the liquid and be forced outwardly againstthe inner periphery of the insulating lining without breakage or ruptureof the bag.

I have illustrated in detail only the bag itself, the tank and theinsulating lining and other features form no part of the presentinvention.

My invention is illustrated more or less diagrammatically in theaccompanying drawings, wherein:

FIGURE 1 is a part vertical section through the tank containing theliquid;

FIGURE 2 is a part vertical section through the tank when empty; and

FIGURE 3 is a horizontal section along the line 2-2 of FIGURES l and 2.

Like parts are indicated by like characters throughout the specificationand drawings.

The cylindrical steel tank has a generally plane steel floor l, avertically disposed generally cylindrical wall 2, and a horizontal roof3. The horizontal roof is apertured centrally at 4. 5 is an insulatingHoor lining which may well be of balsa wood. '6 is an insulating walllining and 7 an insulating roof lining, all three of them containedwithin the steel tank and furnishing adequate insulating inside thesteel walls. `8 is a sleeve concentric with the aperture 4 extendingdownwardly through the insulating roof 7 and flanged at 9 to engage andunderlie the insulation 7. 10 is a collar encircling the sleeve 8 andresting on the steel roof 3.

The aperture thus formed furnishes access to the interior of the tankand may be used for introduction of liquid or gas -by any suitable meansnot here illustrated.

11 is a bag or lining impervious to the liquid, preferably of Wovenglass liber and is impregnated with and coated with any of the suitableimpervious plastics now on the market which remain tlexible under suchlow temperatures as 258 F. This bag provides an effective barrier topenetration of -liquid methane and methane toward and into theinsulating lining. The glass libers, of very small diameter, of whichthe cloth is woven also remain flexible even at such low temperaturesand both the glass fibers and the coating are inert to liquid and togaseous methane at the low temperatures of the liquid in the tank.

I have not illustrated the means whereby the cloth is assembled into abag and whereby the separate sections are cemented together so as tomake a continuous impervious bag as they form no part of the presentinvention.

The bag is generally cylindrical. It has a liat bottom as indicated anda generally ilat top. At the center of the top, the bag is apertured toconform to the aperture through the sleeve 8 and an annular ring 12 isheld against the flange 9 by cap screws or other suitable means l13, sothat the bag is held in place and access may be had through the interiorof the bag through the sleeve 8.

i4 indicates a plurality of flexible supporting straps or hangersattached to the bag by any suitable means around the periphery of thetop of the cylindrical portion of the bag. These hangers are supportedon anchorages l5 ywhich may be, as indicated, carried by the insulatinglining so that the anchorages do not extend clear through the lining andso do not furnish a path for heat condition from the shell 2 to theinterior of the tank. When the tank is empty, it tends to hang loose asindicated in FIGURE 2. When the tank is filled, it tends to expand intocontact with the door and wall of the lining and the pressure ofevaporation may raise the bag from the position shown at i6 at the topof FIGURE 2 to a position such as that shown at 17 in FIGURE 1 and mayeven hold it up against the roof 7 depending on the weight of the top ofthe bag and the pressure generated by evaporation of the liquidhydrocarbon. If found necessary, intermediate hangers may be interposedat other points. As a general proposition such flexible support asindicated in FIGURES 1, 2 and 3 will be entirely suliicient to hold thebag in place so that when the liquid is introduced, there will be aminimum of movement of the bag and a minimum of strain on the bag. Thebag itself does not support the hydrostatic or gaseous pressure in sofar as it is backed up by the insulating lining, which in turn is backedup by the metal shell.

The insulating lining must, of course, be assembled in the shell atordinary room temperatures and the usual tight lining will be installed.However, when the cold liquid is introduced into the tank, thecontraction of the insulating lining as a result of cooling by theliquid may well be greater than the contraction of the shell which is ta very large extent insulated by the insulating lining and there is thepossibility that cracks or voids might appear in the insulating liningand if a liquid impervious bag or other means Were not interposedbetween the insulating lining and the liquid, shrinkage of the liningmight result in such cracks and voids being developed as would permitpenetration of the liquid through the insulating lining into excessivecooling contact with the shell. The bag or liexible lining, however itis supported or formed, prevents such penetration of liquid even if suchvoids or gaps should develop.

I claim:

1. A storage tank of large capacity for housing a liqueed hydrocarboncomposed mostly of methane whereby storage is limited to aboutatmospheric pressure and at a temperature of about -25 8 F. comprisingan outer fluid and vapor impervious metal shell capable of supportingthe liquid load, an inner container of a fluid impervious materialcapable of standing up with the liquefied hydrocarbon gas at about 258F. in the interior thereof and directly in contact therewith, and athick layer of balsa wood completely separating the outer shell andinner container with the balsa Wood insulation arranged as an internallining about the walls of the outer shell and having structural strengthand integrity capable of support4 ing the inner container when filled`with a liquefied hydrocarbon gas to maintain the desired separatedrelationship between the outer shell and inner container.

2. A storage tank of large capacity for housing liquetied methane atabout atmospheric pressure and at a temperature of about -25 8 F.comprising an outer steel shell, an inner shell of a vapor and fluidimpervious material capable of maintaining strength and integrity underthe temperature conditions existing when the liquefied methane isdirectly in contact therewith, and a thick layer of balsa Wood panelslining the inner face of the steel shell to maintain a separatedrelationship between the inner container and the steel shell and tominimize heat transfer therebetween, said thick layer of balsa woodlining having rigidity and structural strength capable of maintainingthe desired spaced relationship between the inner container and themetal shell when the inner container is filled with the liquefiedmethane.

References Cited in the tile of this patent UNITED STATES PATENTS1,003,540 Sterrett Sept. 19, 1911 1,463,498 Burgess July 31, 19231,709,701 Althoif Apr, 16, 1929 2,102,590 Gray Dec. 21, 1937 2,326,263Steiner Aug. 10, 1943 2,381,500 Knudsen et al Aug. 7, 1945 2,564,163Leperre Aug.i14, 1951 2,676,773 Sanz et al Apr. 27, 1954 FOREIGN PATENTS189,848 Great Britain Nov. 30, 1922

